Imaging members with bichromophoric bisazo perylene photoconductive materials

ABSTRACT

Disclosed is an imaging member which comprises a conductive substrate and a photogenerating layer containing a compound selected from the group consisting of: ##STR1## and mixtures thereof, wherein Cp represents a coupler group.

BACKGROUND OF THE INVENTION

The present invention is directed to photoresponsive imaging members.More specifically, the present invention is directed to imaging memberswhich contain photoconductive compounds with an azo moiety and aperylene moiety. One embodiment of the present invention is directed toan imaging member which comprises a conductive substrate and aphotogenerating layer containing a compound selected from the groupconsisting of: ##STR2## and mixtures thereof, wherein Cp represents acoupler group.

Photoresponsive imaging members are known, such as those consisting of ahomogeneous layer of a single material such as vitreous selenium, orcomposite layered devices containing a dispersion of a photoconductivecomposition. An example of a composite xerographic photoconductivemember is described in U.S. Pat. No. 3,121,006, which discloses finelydivided particles of a photoconductive inorganic compound dispersed inan electrically insulating organic resin binder. Imaging membersprepared according to the teachings of this patent contain a binderlayer with particles of zinc oxide uniformly dispersed therein coated ona paper backing. The binders disclosed in this patent include materialssuch as polycarbonate resins, polyester resins, polyamide resins, andthe like, which are incapable of transporting injected charge carriersgenerated by the photoconductive particles for any significant distance.Accordingly, the photoconductive particles must be in a substantiallycontiguous particle to particle contact throughout the layer for thepurpose of permitting the charge dissipation required for a cyclicoperation.

Photoreceptor materials comprising inorganic or organic materialswherein the charge generating and charge transport functions areperformed by discrete contiguous layers are also known. Additionally,layered photoreceptor members are disclosed in the prior art, includingphotoreceptors having an overcoat layer of an electrically insulatingpolymeric material. Other layered photoresponsive devices have beendisclosed, including those comprising separate photogenerating layersand charge transport layers as described in U.S. Pat. No. 4,265,990, thedisclosure of which is totally incorporated herein by reference.Photoresponsive materials containing a hole injecting layer overcoatedwith a hole transport layer, followed by an overcoating of aphotogenerating layer, and a top coating of an insulating organic resin,are disclosed in U.S. Pat. No. 4,251,612, the disclosure of which istotally incorporated herein by reference. Examples of photogeneratinglayers disclosed in these patents include trigonal selenium andphthalocyanines, while examples of transport layers include certain aryldiamines as illustrated therein.

In addition, U.S. Pat. No. 3,041,167 discloses an overcoated imagingmember containing a conductive substrate, a photoconductive layer, andan overcoating layer of an electrically insulating polymeric material.This member can be employed in electrophotographic imaging processes byinitially charging the member with an electrostatic charge of a firstpolarity, followed by exposing it to form an electrostatic latent imagethat can subsequently be developed to form a visible image.

U.S. Pat. No. 3,574,181 discloses disazo compounds useful as coloringagents. Composite electrophotographic photosensitive materialscontaining various azo compounds are disclosed in U.S. Pat. No.4,618,672, wherein bisazo compounds particularly suitable for use in thecharge generating layer of a layered electrophotographic photoconductorare illustrated. Similarly, an article by M. Hashimoto entitled"Electrophotographic Sensitivity of Fluorenone Bisazo Pigments,"Electrophotography, Vol. 25, No. 3 (1986), discloses disazo compounds ascharge generating materials in electrophotographic layeredphotoreceptors. Further, Japanese Patent Kokai No. 54-20736 disclosesdisazo pigments as constituents in electrophotographic processes.Japanese Patent 58-177955 also discloses many disazo compounds suitablefor use in the photosensitive layer of an electrophotographic device.

U.S. Pat. No. 4,713,307, the disclosure of which is hereby totallyincorporated by reference, also discloses photoconductive imagingmembers containing a supporting substrate, certain azo pigments asphotogenerating materials, and a hole transport layer that preferablycontains an aryl diamine compound dispersed in an inactive resinousbinder.

U.S. Pat. No. 4,797,337, the disclosure of which is totally incorporatedherein by reference, discloses a photoconductive imaging membercomprising a supporting substrate, a hole transport layer, and aphotogenerating layer comprising specific disazo compounds.

Additional references illustrating layered organic electrophotographicphotoconductor elements with azo, bisazo, and related compounds includeU.S. Pat. No. 4,390,611, 4,551,404, , 4,596,754, Japanese Patent60-64354, U.S. Pat. Nos. 4,400,455, 4,390,608, 4,327,168, 4,299,896,4,314,015, 4,486,522, 4,486,519, 4,555,667, 90 U.S. 4,440,845,4,486,800, 4,309,611, 4,309,611 4,418,133, 4,293,628, 4,427,753,4,495,264, 4,359,513, 3,898,084, and Japanese Patent Publication60-111247.

U.S. Pat. No. 4,755,443 discloses a photoreceptor for electrophotographywhich comprises a charge carrier generating material and chargetransport material wherein one charge generating material is a metalphthalocyanine or a metal-free phthalocyanine. The layer containing thegenerator material also contains an organic amine. Other carriergenerating substances can be used in combination with the phthalocyaninegenerator material, including azo pigments, anthraquinone dyes, perylenedyes, polycyclic quinone dyes, and methine stearate pigments.

U.S. Pat. No. 4,424,266 discloses an electrophotographic photosensitiveelement having a conductive support and a photosensitive layercomprising a carrier generating phase layer containing a carriergenerating material selected from the group consisting of perylene dyes,polycyclic quinones, and azo dyes, and a carrier transporting phaselayer containing a hydrazone carrier transporting material. The carriergenerator materials can be used either singly or in combination.

U.S. Pat. No. 4,882,254, the disclosure of which is totally incorporatedherein by reference, discloses a layered photoresponsive imaging memberwhich comprises a supporting substrate, a photogenerator layercomprising a mixture of first and second pigments, and an aryl aminehole transport layer. The mixture of pigments is selected from perylenesand phthalocyanines, polycyclic quinones and phthalocyanines, orperinones and phthalocyanines.

Japanese Patent Publication J01-198-763 discloses an electrophotographicphotoreceptor containing a bisazo series compound in a photosensitivelayer formed on a conductive support. A charge transport material isused with the bisazo pigment as a charge generation material, such as2,4,7-trinitrofluorenone, tetracyanoquinodimethane, carbazole,triarylalkane derivatives, phenylenediamine derivatives, hydrazonecompounds, or stilbene derivatives.

Photoresponsive imaging members containing perinone and perylenecompounds are also known. For example, European Patent Publication0040402, DE3019326, filed May 21, 1980, discloses the use ofN,N'-disubstituted perylene-3,4,9,10-tetracarboxyldiimide pigments asphotoconductive substances. Specifically, there is disclosed in thispublication evaporatedN,N'-bis(3-methoxypropyl)perylene-3,4,9,10-tetracarboxyldiimide duallayered negatively charged photoreceptors with improved spectralresponse in the wavelength region of 400 to 700 nanometers. A similardisclosure is contained in Ernst Gunther Schlosser, Journal of AppliedPhotographic Engineering, Vol. 4, No. 3, page 118 (1978). Further, U.S.Pat. No. 3,871,882 discloses photoconductive substances comprisingspecific perylene-3,4,9,10-tetracarboxylic acid derivative dyestuffs.According to the teachings of this patent, the photoconductive layer ispreferably formed by vapor depositing the dyestuff in a vacuum. Thispatent discloses dual layer photoreceptors withperylene-3,4,9,10-tetracarboxylic acid diimide derivatives, which havespectral response in the wavelength region of from 400 to 600nanometers. Additionally, U.S. Pat. No. 3,879,200 discloses imagingmembers with perinones. Furthermore, layered imaging members withimidazole thiazinoperinone photogenerators and related components areillustrated in U.S. Pat. No. 4,517,270 and in Japanese Laid OpenPublications 59-58433/84 and 59-59692/84.

U.S. Pat. No. 4,808,506, the disclosure of which is totally incorporatedherein by reference, discloses a layered photoresponsive imaging memberwhich comprises a supporting substrate, an imidazole perinone comprisingcomponents with a mixture of cis and trans isomers of a specificformula, including trans indanthrene Brilliant Orange, cis indanthreneBordeauxs Red, bis-(4,5-dimethyl)benzimidazole perinone andbis-2,3-naphthimidazole perinone, and an aryl amine hole transportlayer.

U.S. Pat. No. 4,587,189, the disclosure of which is totally incorporatedherein by reference, discloses a photoresponsive imaging membercomprising a supporting substrate, a vacuum evaporated photogeneratorlayer which comprises a perylene pigment.

Imaging members with phthalocyanine materials are also known, asdisclosed in, for example, U.S. Pat. No. 3,594,163, U.S. Pat. No.3,657,272, U.S. Pat. No. 3,816,118, U.S. Pat. No. 3,862,127, U.S. Pat.No. 3,903,107, U.S. Pat. No. 3,927,026, U.S. Pat. No. 3,932,180, U.S.Pat. No. 3,932,454, U.S. Pat. No. 4,031,109, U.S. Pat. No. 4,098,795,and U.S. Pat. No. Re. 27,117, the disclosures of each of which aretotally incorporated herein by reference.

Of background interest is U.S. Pat. No. 4,868,079, which discloses anelectrophotoconductor comprising a conductive support and aphotoconductive layer comprising a resin binder having dispersed thereinan anthranthrone compound, a phthalocyanine compound, and an oxadiazolecompound.

Although known imaging members are suitable for their intended purposes,a need remains for imaging members containing bichromophoricphotoconductive materials. In addition, a need exists for imagingmembers containing photoconductive materials with improvedphotoconductivity. Further, there is a need for imaging memberscontaining photoconductive materials having azo moieties wherein thehole transporting and electron transporting mobility of the azo materialis enhanced. There is also a need for imaging members containingphotoconductive materials having azo moieties and a perylene moietywherein the material has enhanced dispersability in polymers andsolvents. Additionally, a need remains for imaging members containingphotoconductive materials wherein the optical absorption of the materialis increased. A need also remains for photoconductive materials havingincreased optical absorption, thereby enabling the use of reducedamounts of photoconductive material in an imaging member chargegenerating layer and thus improving electrical and environmentalstability of the member. Further, there is a need for photoconductivematerials with enhanced dispersability in polymers and solvents thatenable low cost coating processes in the manufacture of photoconductiveimaging members. Additionally, there is a need for photoconductivematerials that enable imaging members with enhanced photosensitivity inthe infrared wavelength region.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide imaging memberscontaining bichromorphic photoconductive materials.

It is another object of the present invention to provide imaging memberscontaining photoconductive materials with improved photoconductivity.

It is yet another object of the present invention to provide imagingmembers containing photoconductive materials having azo moieties whereinthe hole transporting and electron transporting mobility of the azomaterial is enhanced.

It is still another object of the present invention to provide imagingmembers containing photoconductive materials having azo moieties and aperylene moiety wherein the material has enhanced dispersability inpolymers and solvents.

Another object of the present invention is to provide imaging memberscontaining photoconductive materials wherein the optical absorption ofthe material is increased.

Yet another object of the present invention is to providephotoconductive materials having increased optical absorption, therebyenabling the use of reduced amounts of photoconductive material in animaging member charge generating layer and thus improving electrical andenvironmental stability of the member.

Still another object of the present invention is to providephotoconductive materials with enhanced dispersability in polymers andsolvents that enable low cost coating processes in the manufacture ofphotoconductive imaging members.

It is another object of the present invention to provide photoconductivematerials that enable imaging members with enhanced photosensitivity inthe infrared wavelength region.

These and other objects of the present invention are achieved byproviding an imaging member which comprises a conductive substrate and aphotogenerating layer containing a compound selected from the groupconsisting of: ##STR3## and mixtures thereof, wherein Cp represents acoupler group.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1, 2, 3, and 4 are schematic cross-sectional views of examples ofphotoconductive imaging members of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates schematically one embodiment of the imaging membersof the present invention. Specifically, FIG. 1 shows a photoconductiveimaging member comprising a conductive substrate 1, a photogeneratinglayer 3 comprising a bichromophoric photogenerating compound 2 selectedfrom the group consisting of those compounds represented by Formulae I,II, and III or mixtures thereof optionally dispersed in a resinousbinder composition 4, and a charge transport layer 5, which comprises ahole transporting molecule dispersed in an inactive resinous bindercomposition 9.

FIG. 2 illustrates schematically essentially the same member as thatshown in FIG. 1 with the exception that the hole transport layer issituated between the conductive substrate and the photogenerating layer.More specifically, this Figure illustrates a photoconductive imagingmember comprising a conductive substrate 21, a hole transport layer 23comprising a hole transport composition dispersed in an inactiveresinous binder composition 25, and a photogenerating layer 27comprising a bichromophoric photogenerating compound 28 selected fromthe group consisting of those compounds represented by Formulae I, II,and III or mixtures thereof optionally dispersed in a resinous bindercomposition 29.

FIG. 3 illustrates schematically a photoconductive imaging member of thepresent invention comprising a conductive substrate 31, a hole blockingmetal oxide layer 33, an optional adhesive layer 35, a photogeneratinglayer 37 comprising a bichromophoric photogenerating compound selectedfrom the group consisting of those compounds represented by Formulae I,II, and III or mixtures thereof optionally dispersed in a resinousbinder composition; and an aryl amine hole transport layer 39 comprisingan aryl amine hole transport compound optionally dispersed in a resinousbinder.

FIG. 4 illustrates schematically a photoconductive imaging member of thepresent invention comprising a conductive substrate 41 and aphotogenerating layer 43 comprising a bichromophoric photogeneratingcompound 42 selected from the group consisting of those compoundsrepresented by Formulae I, II, and III or mixtures thereof optionallydispersed in a resinous binder composition 44.

The substrate can be formulated entirely of an electrically conductivematerial, or it can be an insulating material having an electricallyconductive surface. The substrate is of an effective thickness,generally up to about 100 mils, and preferably from about 1 to about 50mils, although the thickness can be outside of this range. The thicknessof the substrate layer depends on many factors, including economic andmechanical considerations. Thus, this layer may be of substantialthickness, for example over 100 mils, or of minimal thickness providedthat there are no adverse effects on the system. In a particularlypreferred embodiment, the thickness of this layer is from about 3 milsto about 10 mils. The substrate can be opaque or substantiallytransparent and can comprise numerous suitable materials having thedesired mechanical properties. The entire substrate can comprise thesame material as that in the electrically conductive surface or theelectrically conductive surface can merely be a coating on thesubstrate. Any suitable electrically conductive material can beemployed. Typical electrically conductive materials include copper,brass, nickel, zinc, chromium, stainless steel, conductive plastics andrubbers, aluminum, semitransparent aluminum, steel, cadmium, silver,gold, paper rendered conductive by the inclusion of a suitable materialtherein or through conditioning in a humid atmosphere to ensure thepresence of sufficient water content to render the material conductive,indium, tin, metal oxides, including tin oxide and indium tin oxide, andthe like. The substrate layer can vary in thickness over substantiallywide ranges depending on the desired use of the electrophotoconductivemember. Generally, the conductive layer ranges in thickness from about50 Angstroms to many centimeters, although the thickness can be outsideof this range. When a flexible electrophotographic imaging member isdesired, the thickness typically is from about 100 Angstroms to about750 Angstroms. The substrate can be of any other conventional material,including organic and inorganic materials. Typical substrate materialsinclude insulating non-conducting materials such as various resins knownfor this purpose including polycarbonates, polyamides, polyurethanes,paper, glass, plastic, polyesters such as Mylar® (available from DuPont) or Melinex 447 (available from ICI Americas, Inc.), and the like.If desired, a conductive substrate can be coated onto an insulatingmaterial. In addition, the substrate can comprise a metallized plastic,such as titanized or aluminized Mylar®, wherein the metallized surfaceis in contact with the photogenerating layer or any other layer situatedbetween the substrate and the photogenerating layer. The coated oruncoated substrate can be flexible or rigid, and can have any number ofconfigurations, such as a plate, a cylindrical drum, a scroll, anendless flexible belt, or the like. The outer surface of the substratepreferably comprises a metal oxide such as aluminum oxide, nickel oxide,titanium oxide, and the like.

In some cases, intermediate adhesive layers between the substrate andsubsequently applied layers may be desirable to improve adhesion. Ifsuch adhesive layers are utilized, they preferably have a dry thicknessof from about 0.1 micron to about 5 microns, although the thickness canbe outside of this range. Typical adhesive layers include film-formingpolymers such as polyester, polyvinylbutyral, polyvinylpyrolidone,polycarbonate, polyurethane, polymethylmethacrylate, and the like aswell as mixtures thereof. Since the surface of the substrate can be ametal oxide layer or an adhesive layer, the expression "substrate" asemployed herein is intended to include a metal oxide layer with orwithout an adhesive layer on a metal oxide layer.

The photogenerating layer contains a bichromophoric photogeneratingcompound of Formulae I, II, or III or a mixture of two or more compoundsof these formulae. Generally, this layer has a thickness of from about0.05 micron to about 10 microns or more, and preferably has a thicknessof from about 0.1 micron to about 3 microns. The thickness of thislayer, however, is dependent primarily upon the concentration ofphotogenerating material in the layer, which may generally vary fromabout 5 to 100 percent. When the photogenerating material is present ina binder material, the binder preferably contains from about 30 to about95 percent by weight of the photogenerating material, and preferablycontains about 80 percent by weight of the photogenerating material.Generally, it is desirable to provide this layer in a thicknesssufficient to absorb about 90 percent or more of the incident radiationwhich is directed upon it in the imagewise or printing exposure step.The maximum thickness of this layer is dependent primarily upon factorssuch as mechanical considerations, such as the specific photogeneratingcompound selected, the thicknesses of the other layers, and whether aflexible photoconductive imaging member is desired.

When present, the optional charge transport layer can comprise anysuitable charge transport material. Examples of charge transportmaterials include pure selenium, selenium-arsenic alloys,selenium-arsenic-halogen alloys, selenium-halogen, and the like.Generally, from about 10 parts by weight per million to about 200 partsby weight per million of halogen are present in a halogen doped seleniumcharge transport layer, although the amount can be outside of thisrange. If a halogen doped transport layer free of arsenic is utilized,the halogen content preferably is less than about 20 parts by weight permillion. Transport layers are well known in the art. Typical transportlayers are described, for example, in U.S. Pat. No. 4,609,605 and inU.S. Pat. No. 4,297,424, the disclosures of each of these patents beingtotally incorporated herein by reference.

Organic charge transport materials can also be employed. Typical chargetransporting materials include the following:

Diamine transport molecules of the type described in U.S. Pat. Nos.4,306,008; 4,304,829; 4,233,384; 4,115,116; 4,299,897 and 4,081,274, thedisclosures of each of which are totally incorporated herein byreference. Typical diamine transport molecules includeN,N'-diphenyl-N,N'-bis(3"-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine,N,N'-diphenyl-N,N'-bis(4-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine,N,N'-diphenyl-N,N'-bis(2-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine,N,N'-diphenyl-N,N'-bis(3-ethylphenyl)-(1,1'-biphenyl)-4,4'-diamine,N,N'-diphenyl-N,N'-bis(4-ethylphenyl)-(1,1'-biphenyl)-4,4'-diamine,N,N'-diphenyl-N,N'-bis(4-n-butylphenyl)-(1,1'-biphenyl)-4,4'-diamine,N,N'-diphenyl-N,N'-bis(3-chlorophenyl)-[1,1'-biphenyl]-4,4'-diamine,N,N'-diphenyl-N,N'-bis(4-chlorophenyl)-[1,1'-biphenyl]-4,4'-diamine,N,N'-diphenyl-N,N'-bis(phenylmethyl)-[1,1'-biphenyl]-4,4'-diamine,N,N,N',N'-tetraphenyl-[2,2'-dimethyl-1,1'-biphenyl]-4,4'-diamine,N,N,N',N'-tetra-(4-methylphenyl)-[2,2'-dimethyl-1,1'-biphenyl]-4,4'-diamine,N,N'-diphenyl-N,N'-bis(4-methylphenyl)-[2,2'-dimethyl-1,1'-biphenyl]-4,4'-diamine,N,N'-diphenyl-N,N'-bis(2-methylphenyl)-[2,2'-dimethyl-1,1'-biphenyl]-4,4'-diamine,N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[2,2'-dimethyl-1,1'-biphenyl]-4,4'-diamine,N,N'-diphenyl-N,N'-bis(3-methylphenyl)-pyrenyl-1,6-diamine, and thelike.

Pyrazoline transport molecules as disclosed in U.S. Pat. Nos. 4,315,982;4,278,746 and 3,837,851, the disclosures of each of which are totallyincorporated herein by reference. Typical pyrazoline transport moleculesinclude1-[lepidyl-(2)]-3-(p-diethylaminophenyl)-5-(p-diethylaminophenyl)pyrazoline,1-[quinolyl-(2)]-3-(p-diethylaminophenyl)-5-(p-diethylaminophenyl)pyrazoline,1-[pyridyl-(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline,1-[6-methoxypyridyl-(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline,1-phenyl-3-[p-dimethylaminostyryl]-5-(p-dimethylaminostyryl)pyrazoline,1-phenyl-3-[p-diethylaminostyryl]-5-(p-diethylaminostyryl)pyrazoline,and the like.

Substituted fluorene charge transport molecules as described in U.S.Pat. No. 4,245,021, the disclosure of which is totally incorporatedherein by reference. Typical fluorene charge transport molecules include9-(4'-dimethylaminobenzylidene)fluorene,9-(4'-methoxybenzylidene)fluorene,9-(2',4'-dimethoxybenzylidene)fluorene, 2-nitro-9-benzylidene-fluorene,2-nitro-9-(4'-diethylaminobenzylidene)fluorene, and the like.

Oxadiazole transport molecules such as2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole, pyrazoline, imidazole,triazole, and the like. Other typical oxadiazole transport molecules aredescribed, for example, in German Patents 1,058,836; 1,060,260 and1,120,875, the disclosures of each of which are totally incorporatedherein by reference.

Hydrazone transport molecules, such as p-diethylaminobenzaldehyde-(diphenylhydrazone),o-ethoxy-p-diethylaminobenzaldehyde-(diphenylhydrazone),o-methyl-p-diethylaminobenzaldehyde-(diphenylhydrazone),o-methyl-p-dimethylaminobenzaldehyde-(diphenylhydrazone),1-naphthalenecarbaldehyde 1-methyl-1-phenylhydrazone,1-naphthalenecarbaldehyde 1,1-phenylhydrazone,4-methoxynaphthalene-1-carbaldehyde 1-methyl-1-phenylhydrazone, and thelike. Other typical hydrazone transport molecules are described, forexample, in U.S. Pat. Nos. 4,150,987, 4,385,106, 4,338,388 and4,387,147, the disclosures of each of which are totally incorporatedherein by reference.

Carbazole phenyl hydrazone transport molecules such as9-methylcarbazole-3-carbaldehyde-1,1-diphenylhydrazone,9-ethylcarbazole-3-carbaldehyde-1-methyl-1-phenylhydrazone,9-ethylcarbazole-3-carbaldehyde-1-ethyl-1-phenylhydrazone,9-ethylcarbazole-3-carbaldehyde-1-ethyl-1-benzyl-1-phenylhydrazone,9-ethylcarbazole-3-carbaldehyde-1,1-diphenylhydrazone, and the like.Other typical carbazole phenyl hydrazone transport molecules aredescribed, for example, in U.S. Pat. Nos. 4,256,821 and 4,297,426, thedisclosures of each of which are totally incorporated herein byreference.

Vinyl-aromatic polymers such as polyvinyl anthracene,polyacenaphthylene; formaldehyde condensation products with variousaromatics such as condensates of formaldehyde and 3-bromopyrene;2,4,7-trinitrofluorenone, and 3,6-dinitro-N-t-butylnaphthalimide asdescribed, for example, in U.S. Pat. No. 3,972,717, the disclosure ofwhich is totally incorporated herein by reference.

Oxadiazole derivatives such as2,5-bis-(p-diethylaminophenyl)oxadiazole-1,3,4 described in U.S. Pat.No. 3,895,944, the disclosure of which is totally incorporated herein byreference.

Tri-substituted methanes such as alkyl-bis(N,N-dialkylaminoaryl)methane,cycloalkyl-bis(N,N-dialkylaminoaryl)methane, andcycloalkenyl-bis(N,N-dialkylaminoaryl)methane as described in U.S. Pat.No. 3,820,989, the disclosure of which is totally incorporated herein byreference.

9-Fluorenylidene methane derivatives having the formula ##STR4## whereinX and Y are cyano groups or alkoxycarbonyl groups, A, B, and W areelectron withdrawing groups independently selected from the groupconsisting of acyl, alkoxycarbonyl, nitro, alkylaminocarbonyl, andderivatives thereof, m is a number of from 0 to 2, and n is the number 0or 1 as described in U.S. Pat. No. 4,474,865, the disclosure of which istotally incorporated herein by reference. Typical 9-fluorenylidenemethane derivatives encompassed by the above formula include(4-n-butoxycarbonyl-9-fluorenylidene)malononitrile,(4-phenethoxycarbonyl-9-fluorenylidene)malononitrile,(4-carbitoxy-9-fluorenylidene)malononitrile,(4-n-butoxycarbonyl-2,7-dinitro-9-fluorenylidene)malonate, and the like.

Other charge transport materials include poly-1-vinylpyrene,poly-9-vinylanthracene, poly-9-(4-pentenyl)-carbazole,poly-9-(5-hexyl)-carbazole, polymethylene pyrene,poly-1-(pyrenyl)-butadiene, polymers such as alkyl, nitro, amino,halogen, and hydroxy substitute polymers such as poly-3-amino carbazole,1,3-dibromo-poly-N-vinyl carbazole, 3,6-dibromo-poly-N-vinyl carbazole,and numerous other transparent organic polymeric or non-polymerictransport materials as described in U.S. Pat. No. 3,870,516, thedisclosure of which is totally incorporated herein by reference.

A particularly preferred charge transport molecule is one having thegeneral formula ##STR5## wherein X, Y and Z are selected from the groupconsisting of hydrogen, an alkyl group having from 1 to about 20 carbonatoms and chlorine, and at least one of X, Y and Z is independentlyselected to be an alkyl group having from 1 to about 20 carbon atoms orchlorine. If Y and Z are hydrogen, the compound may be namedN,N'-diphenyl-N,N'-bis(alkylphenyl)-[1,1'-biphenyl]-4,4'-diamine whereinthe alkyl is, for example, methyl, ethyl, propyl, n-butyl, or the like,or the compound may beN,N'-diphenyl-N,N'-bis(chlorophenyl)-[1,1'-biphenyl]-4,4'-diamine.

The charge transport material is present in the charge transport layerin an effective amount, generally from about 5 to about 90 percent byweight, preferably from about 20 to about 75 percent by weight, and morepreferably from about 30 to about 60 percent by weight, although theamount can be outside of this range.

Examples of the highly insulating and transparent resinous components orinactive binder resinous material for the transport layers includematerials such as those described in U.S. Pat. No. 3,121,006, thedisclosure of which is totally incorporated herein by reference.Specific examples of suitable organic resinous materials includepolycarbonates, acrylate polymers, vinyl polymers, cellulose polymers,polyesters, polysiloxanes, polyamides, polyurethanes, polystyrenes, andepoxies as well as block random or alternating copolymers thereof.Preferred electrically inactive binder materials are polycarbonateresins having a molecular weight of from about 20,000 to about 100,000with a molecular weight in the range of from about 50,000 to about100,000 being particularly preferred. Generally, the resinous bindercontains from about 5 to about 90 percent by weight of the activematerial corresponding to the foregoing formula, and preferably fromabout 20 percent to about 75 percent of this material.

Similar binder materials may be selected for the photogenerating layer,including polyesters, polyvinyl butyrals, polycarbonates, polyvinylformals, and those illustrated in U.S. Pat. No. 3,121,006, thedisclosure of which is totally incorporated herein by reference. Apreferred class of binder material for the photogenerating layer is apoly (vinyl acetal).

The photoconductive imaging member may optionally contain a chargeblocking layer situated between the conductive substrate and thephotogenerating layer. This layer may comprise metal oxides, such asaluminum oxide and the like, or materials such as silanes and nylons.Additional examples of suitable materials include polyisobutylmethacrylate, copolymers of styrene and acrylates such asstyrene/n-butyl methacrylate, copolymers of styrene and vinyl toluene,polycarbonates, alkyl substituted polystyrenes, styrene-olefincopolymers, polyesters, polyurethanes, polyterpenes, siliconeelastomers, mixtures thereof, copolymers thereof, and the like. Theprimary purpose of this layer is to prevent charge injection from thesubstrate during and after charging. This layer is of a thickness ofless than 50 Angstroms to about 10 microns, preferably being no morethan about 2 microns.

In addition, the photoconductive imaging member may also optionallycontain an adhesive interface layer situated between the hole blockinglayer and the photogenerating layer. This layer may comprise a polymericmaterial such as polyester, polyvinyl butyral, polyvinyl pyrrolidone andthe like. Typically, this layer is of a thickness of less than about 0.6micron.

The bichromophoric photogenerating pigments employed in the imagingmembers of the present invention are of the following formulae: ##STR6##wherein Cp represents a coupler group. The photogenerating compound canbe symmetrical and contain two identical coupler groups or unsymmetricaland contain two different coupler groups. Most coupler groups arearomatic hydrocarbon compounds or heterocyclic compounds with a phenolichydroxy group, such as 2-naphthol derivatives, although other couplersare also suitable. Examples of suitable coupler groups include ##STR7##wherein X₁ represents --OH, --NR₁ R₂, or --NHSO₂ --R₃ (wherein R₁ and R₂are hydrogen or a substituted or non-substituted alkyl group and R₃ is asubstituted or non-substituted alkyl or a substituted or non-substitutedaryl group), Y₁ represents hydrogen, halogen, substituted ornon-substituted alkyl groups, substituted or non-substituted alkoxygroups, carboxyl group, sulfo group, substituted or non-substitutedsulfamoyl groups, or ##STR8## (wherein R₄ is hydrogen, an alkyl group, asubstituted alkyl group, a phenyl group, or a substituted phenyl group,and Y₂ is a cyclic hydrocarbon, a substituted cyclic hydrocarbon, aheterocycle, or a substituted heterocycle, or ##STR9## wherein R₅represents a cyclic hydrocarbon, a substituted cyclic hydrocarbon, aheterocycle, or a substituted heterocycle and R₆ represents hydrogen, analkyl group, a substituted alkyl group, a phenyl group, or a substitutedphenyl group, and wherein R₅ and R₆ may form a ring with carbons bondedthereto), Z represents a cyclic hydrocarbon or a substituted cyclichydrocarbon, or a heterocycle or a substituted heterocycle, n is aninteger of 1 or 2, m is an integer of 1 or 2, R₇ is a substituted ornon-substituted hydrocarbonyl group, R₈ is an alkyl group, a carbamoylgroup, a carboxyl group, or a carboxyl ester, Ar₁ is a cyclichydrocarbon or a substituted cyclic hydrocarbon, R₉ is hydrogen or asubstituted or non-substituted hydrocarbonyl group, and Ar₂ is a cyclichydrocarbon or a substituted cyclic hydrocarbon. Specific examples ofthe cyclic hydrocarbon ring Z include a benzene ring, a naphthalenegroup, or the like, as well as heterocycles such as an indole ring, acarbazole ring, a benzofuran ring, and the like. Examples ofsubstituents for the Z ring include halogen atoms such as chlorine,fluorine, iodine, or bromine and the like. Examples of the cyclichydrocarbon Y₂ or R₅ include phenyl, naphthyl, anthryl, pyrenyl, and thelike, as well as heterocycles such as pyridyl, thienyl, furyl, indolyl,benzofuranyl, carbazolyl, dibenzofuranyl, and the like. Examples of thering formed by bonding R₅ and R₆ include a fluorene ring. Examples ofsubstituents for Y₂ and R₅ or the ring formed by bonding R₅ and R₆include alkyl groups such as methyl, ethyl, propyl, butyl, or the like,alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, or the like,halogen atoms such as chlorine, fluorine, bromine, iodine, or the like,dialkyl amino groups such as dimethyl amino, diethyl amino, or the like,diaralkyl amino groups such as dibenzyl amino or the like, halomethylgroups such as trifluoromethyl or the like, a nitro group, a cyanogroup, a carboxyl group or an ester, a hydroxyl group, a sulfonate groupsuch as --SO₃ Na, or the like. Examples of substituents for group R₄include halogen atoms such as chlorine, fluorine, bromine, or iodine andthe like. Examples of hydrocarbonyl groups R₇ and R₉ include alkylgroups such as methyl, ethyl, propyl, butyl, and the like, aralkylgroups such as benzyl and the like, aryl groups such as phenyl, or thelike, as well as substituted groups. Examples of substituents for R₇ andR₉ include alkyl groups such as methyl, ethyl, propyl, butyl, or thelike, alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, or thelike, halogen atoms such as chlorine, bromine, fluorine, iodine, or thelike, a hydroxyl group, a nitro group, and the like. Examples of cyclichydrocarbons Ar₁ and Ar₂ include phenyl, naphthyl, and the like, andexamples of substituents for these groups include alkyl groups such asmethyl, ethyl, propyl, butyl, or the like, alkoxy groups such asmethoxy, ethoxy, propoxy, butoxy, or the like, a nitro group, a halogengroups such as chlorine, bromine, fluorine, iodine, or the like, a cyanogroup, a dialkyl amino group such as dimethyl amino, diethyl amino, orthe like.

Specific examples of suitable coupler groups include ##STR10## wherein Ris a substituted or non-substituted aliphatic linear or branchedhydrocarbon with from 1 to about 20 carbon atoms, preferably with from 1to about 10 carbon atoms, and Ar is a substituted or non-substitutedaromatic hydrocarbon group with from 6 to about 24 carbon atoms orheterocyclic moiety; ##STR11## wherein R is a substituted ornon-substituted aliphatic linear or branched hydrocarbon with from 1 toabout 20 carbon atoms, preferably with from 1 to about 10 carbon atoms,and Ar is a substituted or non-substituted aromatic hydrocarbon groupwith from 6 to about 24 carbon atoms or heterocyclic moiety; ##STR12##wherein R is a substituted or non-substituted aliphatic linear orbranched hydrocarbon with from 1 to about 20 carbon atoms, preferablywith from 1 to about 10 carbon atoms, and Ar is a substituted ornon-substituted aromatic hydrocarbon group with from 6 to about 24carbon atoms or heterocyclic moiety; ##STR13## wherein R is asubstituted or non-substituted aliphatic linear or branched hydrocarbonwith from 1 to about 20 carbon atoms, preferably with from 1 to about 10carbon atoms, and Ar is a substituted or non-substituted aromatichydrocarbon group with from 6 to about 24 carbon atoms or heterocyclicmoiety; ##STR14## wherein X is selected from the group consisting of H,CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, l, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, OH, orother substituents and n is 0, 1,2, or 3; ##STR15## wherein X and Y areindependently selected from the group consisting of H, CH₃, C₂ H₅, C₃H₇, Cl, F, Br, l, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, OH, or othersubstituents, m is 0,1,2,3, or 4, and n is 0, 1,2, or 3; ##STR16##wherein X is selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇,Cl, F, Br, l, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, OH, or other substituentsand n is 0, 1,2, or 3; ##STR17## wherein X is selected from the groupconsisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, l, NO₂, CF₃, OCH₃, OC₂H₅, CN, NH₂, OH, or other substituents and n is 0, 1, 2, or 3; or anyother suitable coupler group. Additional examples of coupler groups aredisclosed in, for example, U.S. Pat. No. 4,666,805, the disclosure ofwhich is totally incorporated herein by reference.

Additional examples of suitable couplers include2-hydroxy-3-naphthanilide, 2-hydroxy-3-naphtho-o-nitroanilide, and2-hydroxy-3-naphtho-p-nitroanilide, all available from Aldrich ChemicalCompany; 2-hydroxy-3-naphtho-o-methoxyanilide,2-hydroxy-3-naphtho-p-methoxyanilide,2-hydroxy-3-naphtho-o-methylanilide,2-hydroxy-3-naphtho-p-chloroanilide, 2-hydroxy-3-naphtho-m-nitroanilide,all available from Pfaltz & Bauer Company; Naphthol AS-SG and NaphtholAS-GR, available from Sigma Corporation;2-hydroxy-3-naphtho-p-methylanilide,2-hydroxy-3-naphtho-m-methylanilide,2-hydroxy-3-naphtho-p-fluoroanilide,2-hydroxy-3-naphtho-o-fluoroanilide,2-hydroxy-3-naphtho-o-chloroanilide,2-hydroxy-3-naphtho-m-chloroanilide, 2-hydroxy-3-naphtho-p-bromoanilide,2-hydroxy-3-naphtho-o-bromoanilide,2-hydroxy-3-naphtho-p-trifluoromethylanilide,2-hydroxy-3-naphtho-m-trifluoromethylanilide,2-hydroxy-3-naphtho-o-ethylanilide,3-hydroxy-1,8-benzimidazole-naphthalene,N-phenyl-3-hydroxyl-1,8-naphthalimide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-anilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-p-methylanilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-o-methylanilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-o-ethylanilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-p-fluoroanilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-m-fluoroanilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-p-chloroanilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-m-chloroanilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-o-chloroanilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-p-bromoanilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-o-trifluoromethylanilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-p-trifluoromethylanilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-m-nitroanilide,2-hydroxy-11H-benzo(a)carbazole-3-carbox-p-nitroanilide,2-hydroxy-8-chloro-11H-benzo(a)carbazole-3-carbox-anilide,2-hydroxy-8-chloro-11H-benzo(a)carbazole-3-carbox-p-chloroanilide,2-hydroxy-8-chloro-11H-benzo(a)carbazole-3-carbox-p-fluoroanilide,2-hydroxy-8-chloro-11H-benzo(a)carbazole-3-carbox-o-methylanilide, andthe like. Coupler compounds can also be synthesized by the methoddisclosed in German Patent 2,410,723, the disclosure of which is totallyincorporated herein by reference.

The bichromophoric photogenerating pigments employed in the imagingmembers of the present invention can be prepared by any suitableprocess. For example, to prepare a compound of Formula I,3,4,9,10-perylenetetracarboxylic dihydride can be reacted withm-phenylenediamine to produceN,N'-bis(3-aminophenyl)-3,4,9,10-perylenetetracarboxylic diimide asfollows: ##STR18## Alternatively, theN,N'-bis(3-aminophenyl)-3,4,9,10-perylenetetracarboxylic diimideproduced by this reaction can be obtained commercially, from, forexample, Aldrich Chemical Company Subsequently,N,N'-bis(3-aminophenyl)-3,4,9,10-perylenetetracarboxylic diimide can bereacted with aqueous hydrochloric acid, aqueous sodium nitrite, andtetrafluoboric acid to form a tetrazonium salt as follows: ##STR19##Thereafter, the tetrazonium salt can be reacted with the couplercompound of choice (2-hydroxy-3-naphthanilide is illustated) in thepresence of a base catalyst, such as sodium acetate, to form abichromophoric compound of Formula I: ##STR20##

As illustrated, the process entailed beginning with metaphenylenediamineand resulted in formation of a compound with the azo groups in the metapositions with respect to the perylene moiety. Beginning withortho-phenylenediamine or para-phenylenediamine will result in formationof compounds with the azo groups in the ortho and para positions,respectively, with respect to the perylene moiety.

As an example of a process to prepare compounds of Formulas II and III,3,4,9,10-perylenetetracarboxylic dihydride can be reacted with1,2,4-triaminobenzene as follows: ##STR21## Subsequently, the compoundthus formed can be reacted with aqueous hydrochloric acid, aqueoussodium nitrite, and tetrafluoboric acid to form a tetrazonium salt asfollows: ##STR22## Thereafter, the tetrazonium salt can be reacted withthe coupler compound of choice (2-hydroxy-3-naphthanilide isillustrated) in the presence of a base catalyst, such as sodium acetate,to form bichromophoric compounds of Formulae II and III: ##STR23##

The photogenerating compounds of the present invention enable enhancedphotosensitivity in the infrared wavelength range. In particular,compounds of Formulae II and III enhance photosenstivity at wavelengthsof up to about 700 nanometers, which renders them particularly usefulfor applications such as LED printing processes, which typically requiresensitivity of about 680 nanometers.

The present invention also encompasses a method of generating imageswith the photoconductive imaging members disclosed herein. The methodcomprises the steps of generating an electrostatic latent image on aphotoconductive imaging member of the present invention, developing thelatent image, and transferring the developed electrostatic image to asubstrate. Optionally, the transferred image can be permanently affixedto the substrate. Development of the image may be achieved by a numberof methods, such as cascade, touchdown, powder cloud, magnetic brush,and the like. Transfer of the developed image to a substrate may be byany method, including those making use of a corotron or a biased roll.The fixing step may be performed by means of any suitable method, suchas flash fusing, heat fusing, pressure fusing, vapor fusing, and thelike. Any material used in xerographic copiers and printers may be usedas a substrate, such as paper, transparency material, or the like.

Specific embodiments of the invention will now be described in detail.These examples are intended to be illustrative, and the invention is notlimited to the materials, conditions, or process parameters set forth inthese embodiments. All parts and percentages are by weight unlessotherwise indicated.

EXAMPLE I

A photogenerating compound(N,N'-bis[3-(1'-azo-2'-hydroxy-3'-naphthanilide)phenyl]-3,4,9,10-perylenetetracarboxylic diimide) of the formula ##STR24## was prepared asfollows. N,N'-bis(3-aminophenyl)-3,4,9,10-perylenetetracarboxylicdiimide (1.43 grams, 2.5 millimoles, obtained from Aldrich ChemicalCompany) was stirred in an aqueous solution containing 10 milliliters ofconcentrated hydrochloric acid and 10 milliliters of water at about 60°C. for 1 hour and subsequently stirred overnight at room temperature.The resulting dispersion was cooled to 0° to 5° C. by an ice water bath,and a cold aqueous solution of sodium nitrite (0.6 gram in 1.3milliliters of water) was added dropwise over 15 minutes. The azotizedmixture was stirred for 1 hour and was poured into a 700 milliliterbeaker. The mixture was then diluted with cold water to a total volumeof about 400 milliliters, and was filtered through a (medium) sinteredglass funnel. Subsequently, 20 milliliters of HBF₄ were added to the redfiltrate solution, resulting in formation of a red precipitate (thetetrazonium salt ofN,N'-bis(3-aminophenyl)-3,4,9,10-perylenetetracarboxylic diimide) whichwas collected by filtration. The tetrazonium salt was then dissolved inabout 100 milliliters of cold dimethyl formamide inside a 1 liter 3 neckflask surrounded by an ice water bath. A cold dimethyl formamidesolution containing 1.31 grams of 2-hydroxy-3-naphthanilide obtainedfrom Aldrich Chemical Company in 100 milliliters of dimethyl formamidewas added to the salt solution, resulting in the solution color turningfrom red to brown. Subsequently, a cold aqueous solution of sodiumacetate (2.67 grams NaOAc in 40 milliliters of water) was added dropwiseto the solution, resulting in formation of a brown precipitate. Thebrown precipitate was stirred at room temperature overnight, followed byisolation of the product by filtration. The product was then purified bywashing twice with 150 milliliter aliquots of water at 80° C., followedby washing three times with 150 milliliter aliquots of dimethylformamide at 80° C., subsequently washing with 150 milliliters ofacetone, and then washing with 150 milliliters of diethyl ether,resulting in 1.62 grams (59 percent overall yield) of a brown solidhaving a melting point of over 300° C. The infrared spectrum of thisproduct in KBr exhibited peaks at 1705 and 1671 (C═O) cm⁻¹. In addition,an elemental analysis was performed which further identified the productas the photogenerating pigment of the above formula:

calculated for C₇₀ H₄₀ N₈ O₈ : C 74.99; H 3.60; N 9.99.

actual composition: C 74.33; H 3.78; N 9.63.

EXAMPLE II

An imaging member was prepared with the photogenerating pigment preparedin Example I as follows. To a 1 ounce amber bottle there were added 52.8milligrams of polyvinyl formal (obtained from Scientific PolymerProducts, Inc., formal content 82 percent, acetate content 12 percent,hydroxy content 6 percent) and 10 milliliters of tetrahydrofuran. Thebottle was placed on a Wrist Action Shaker and the polymer was dissolvedin the tetrahydrofuran. Subsequently, 211.2 milligrams of thephotogenerating material prepared in Example I and about 85 grams ofsteel shots (1/8 inch diameter stainless steel shot) were added to thebottle and the bottle was placed on a Red Devil Paint Conditioner (Model5100X) and shaken for about 30 minutes. The resulting dispersion wascoated onto a 7.5 inch by 10 inch fire-cleaned brush-grained aluminumsubstrate obtained from Ron Ink Company using a Gardner Mechanical Drivewith a 6 inch wide Bird Film Applicator (0.5 mil wet gap) inside ahumidity-controlled glove-box. The relative humidity was controlled toless than 25 percent. The resulting charge generator layer was air driedfor about 30 minutes and then vacuum dried for about 1 hour at 100° C.The thickness of the charge generator layer was estimated to be about0.4 micron from TEM micrographs.

The above charge generator layer was overcoated with a charge transportlayer prepared as follows. A solution containing 4.2 grams of Makrolon®,a polycarbonate resin obtained from Larbensabricken Bayer A. G., 2.8grams of N,N'-bis(3"-methylphenyl)-1,1'-biphenyl-4,4'-diamine preparedas disclosed in U.S. Pat. No. 4,265,990, the disclosure of which istotally incorporated herein by reference, was prepared by dissolving theabove materials in 31 milliliters of methylene chloride inside a 2 ounceamber bottle. The transport layer was obtained by coating the solutiononto the charge generator layer using a 3.5 inch wide, 5 mil wet gapBird Film Applicator, resulting in a transport layer about 25 micronsthick. The resulting photoconductive device was air dried for about 1hour and vacuum dried at 100° C. for about 16 hours before electricaltesting.

The imaging member thus prepared was evaluated as follows. Xerographicmeasurements were made on a flat plate scanner using 2 inch by 2.5 inchsamples of the imaging member prepared as described herein. The surfacepotential of the device was monitored with a capacitively coupled ringprobe connected to a Keithley electrometer (Model 610C) in the Coulombmode. The output of the electrometer was displayed on a strip-chartrecorder (HP Model 740A) which was calibrated by applying known voltageon an uncoated aluminum substrate. The exposure wavelength and theintensity were selected and adjusted using interference and neutraldensity filters, respectively. With the shutter closed, the dark decaywas measured. With the shutter open, the photosensitivity at a knownlight exposure was recorded. The imaging member was charged to about-1000 volts at the peak voltage and was allowed to discharge in the darkfor 2 to 3 seconds to determine the dark decay. Subsequently, theimaging member was exposed to an erase lamp to photodischarge thesurface charge and to determine its residual voltage (V_(R)).Thereafter, the imaging member was charged in a similar manner andexposed to visible radiation at the dark development potential, and thesensitivity of the member was determined in terms of E_(1/2), whichrepresents the energy required to discharge half of the dark developmentpotential. The imaging member exhibited a dark development potential(V_(ddp)) of -980 volts, a dark decay of -12 volts per second, and aresidual potential (V_(R)) of -5 volts. The imaging member exhibitedphotosensitivity in the 400 to 650 nanometer range, with the sensitivity(E_(1/2)) being measured under varying wavelengths of light as follows:

    ______________________________________                                        Wavelength (nm) E.sub.1/2  (ergs/cm.sup.2)                                    ______________________________________                                        400             14.4                                                          450             4.0                                                           520             4.6                                                           550             3.8                                                           600             6.7                                                           650             34.3                                                          ______________________________________                                    

As the data indicate, the imaging member exhibits photosensitivity inthe measured wavelength range.

EXAMPLE III

A photogenerating compound (N,N'-bis[3-(1'-azo-2'-hydroxy-11'Hbenzo(a)carbazole-3'-carbox-p-methoxyanilide)phenyl]-3,4,9,10-perylenetetracarboxylic diimide) of the formula ##STR25## was prepared asfollows. N,N'-bis(3-aminophenyl)-3,4,9,10-perylenetetracarboxylicdiimide (1.43 grams, 2.5 millimoles, obtained from Aldrich ChemicalCompany) was stirred in an aqueous solution containing 10 milliliters ofconcentrated hydrochloric acid and 10 milliliters of water at about 60°C. for 1 hour and subsequently stirred overnight at room temperature.The resulting dispersion was cooled to 0° to 5° C. by an ice water bath,and a cold aqueous solution of sodium nitrite (0.6 grams in 1.3milliliters of water) was added dropwise over 15 minutes. The azotizedmixture was stirred for 1 hour and was poured into a 700 milliliterbeaker. The mixture was then diluted with cold water to a total volumeof about 400 milliliters, and was filtered through a (medium) sinteredglass funnel. Subsequently, 20 milliliters of HBF₄ was added to the redfiltrate solution, resulting in formation of a red precipitate(tetrazonium salt ofN,N'-bis(3-aminophenyl)-3,4,9,10-perylenetetracarboxylic diimide) whichwas collected by filtration. The tetrazonium salt was then dissolved inabout 100 milliliters of cold dimethyl formamide inside a 1 liter 3 neckflask surrounded by an ice water bath. A cold dimethyl formamidesolution containing 1.91 grams of Naphthol AS-SG obtained from SigmaChemical Company in 100 milliliters of dimethyl formamide was added tothe salt solution, resulting in the solution color turning from red todark brown. Subsequently, a cold aqueous solution of sodium acetate(2.67 grams NaOAc in 40 milliliters of water) was added dropwise to thesolution, resulting in formation of a black precipitate. The blackprecipitate was stirred at room temperature overnight, followed byisolation of the product by filtration. The product was then purified bywashing twice with 150 milliliter aliquots of water at 80° C., followedby washing three times with 150 milliliter aliquots of dimethylformamide at 80° C., subsequently washing with 150 milliliters ofacetone, and then washing with 150 milliliters of diethyl ether,resulting in 1.98 grams (59 percent overall yield) of a black solidhaving a melting point of over 300° C. The infrared spectrum of thisproduct in KBr exhibited peaks at 1704 and 1670 (C═O) cm⁻¹. In addition,an elemental analysis was performed which further identified the productas the photogenerating pigment of the above formula:

calculated for C₈₄ H₅₀ N₁₀ O₈ : C 76.01; H 3.80; N 10.35.

actual composition: C 75.39; H 3.86; N 9.93.

EXAMPLE IV

An imaging member was prepared with the photogenerating pigment preparedin Example III as follows. To a 1 ounce amber bottle there were added52.8 milligrams of polyvinyl formal (obtained from Scientific PolymerProducts, Inc., formal content 82 percent, acetate content 12 percent,hydroxy content 6 percent) and 10 milliliters of tetrahydrofuran. Thebottle was placed on a Wrist Action Shaker and the polymer was dissolvedin the tetrahydrofuran. Subsequently, 211.2 milligrams of thephotogenerating material prepared in Example III and about 85 grams ofsteel shots (1/8 inch diameter stainless steel shot) were added to thebottle and the bottle was placed on a Red Devil Paint Conditioner (Model5100X) and shaken for about 30 minutes. The resulting dispersion wascoated onto a 7.5 inch by 10 inch fire-cleaned brush-grained aluminumsubstrate obtained from Ron Ink Company using a Gardner Mechanical Drivewith a 6 inch wide Bird Film Applicator (0.5 mil wet gap) inside ahumidity-controlled glove-box. The relative humidity was controlled toless than 25 percent. The resulting charge generator layer was air driedfor about 30 minutes and then vacuum dried for about 1 hour at 100° C.The thickness of the charge generator layer was estimated to be about0.4 micron from TEM micrographs.

The above charge generator layer was overcoated with a charge transportlayer prepared as follows. A solution containing 4.2 grams of Makrolon®,a polycarbonate resin obtained from Larbensabricken Bayer A. G., 2.8grams of N,N'-bis (3"-methylphenyl)-1,1'-biphenyl-4,4'-diamine preparedas disclosed in U.S. Pat. No. 4,265,990, the disclosure of which istotally incorporated herein by reference, was prepared by dissolving theabove materials in 31 milliliters of methylene chloride inside a 2 ounceamber bottle. The transport layer was obtained by coating the solutiononto the charge generator layer using a 3.5 inch wide, 5 mil wet gapBird Film Applicator, resulting in a transport layer about 25 micronsthick. The resulting photoconductive device was air dried for about 1hour and vacuum dried at 100° C. for about 16 hours before electricaltesting.

The imaging member thus prepared was evaluated as follows. Xerographicmeasurements were made on a flat plate scanner using 2 inch by 2.5 inchsamples of the imaging member prepared as described herein. The surfacepotential of the device was monitored with a capacitively coupled ringprobe connected to a Keithley electrometer (Model 610C) in the Coulombmode. The output of the electrometer was displayed on a strip-chartrecorder (HP Model 740A) which was calibrated by applying known voltageon an uncoated aluminum substrate. The exposure wavelength and theintensity were selected and adjusted using interference and neutraldensity filters, respectively. With the shutter closed, the dark decaywas measured. With the shutter open, the photosensitivity at a knownlight exposure was recorded. The imaging member was charged to about-1000 volts at the peak voltage and was allowed to discharge in the darkfor 2 to 3 seconds to determine the dark decay. Subsequently, theimaging member was exposed to an erase lamp to photodischarge thesurface charge and to determine its residual voltage (V_(R)).Thereafter, the imaging member was charged in a similar manner andexposed to visible radiation at the dark development potential, and thesensitivity of the member was determined in terms of E_(1/2), whichrepresents the energy required to discharge half of the dark developmentpotential. The imaging member exhibited a dark development potential(V_(ddp)) of -980 volts, a dark decay of -22 volts per second, and aresidual potential (V_(R)) of -15 volts. The imaging member exhibitedphotosensitivity in the 400 to 650 nanometer range, with the sensitivity(E_(1/2)) being measured under varying wavelengths of light as follows:

    ______________________________________                                        Wavelength (nm) E.sub.1/2  (ergs/cm.sup.2)                                    ______________________________________                                        400             137.0                                                         450             44.0                                                          520             38.9                                                          550             35.7                                                          600             35.8                                                          650             58.0                                                          ______________________________________                                    

As the data indicate, the imaging member exhibits photosensitivity inthe measured wavelength range.

EXAMPLE V

Photogenerating compounds of the formulae ##STR26## are prepared asfollows. In a 250 milliliter flask are mixed 3.92 grams (0.01 mole) of3,4,9,10-perylenetetracarboxylic dianhydride (available from AldrichChemical Company), 6.15 grams (0.05 mole) of 1,2,4-triaminobenzene(available from Eastman Kodak Company), and 100 milliliters of1-methyl-2-pyrrolidinone. The mixture is brought to reflux with stirringfor 8 hours (oil bath temperature 240° C.). The resulting productmixture is cooled to about 90° C. and is filtered hot, and the solidproduct thus obtained is then purified by washing once with 150milliliters of methanol, subsequently washing twice with 100 milliliteraliquots of an aqueous 5 percent Na₂ CO₃ solution, thereafter washingonce with 100 milliliters of water, and then washing once again with 100milliliters of methanol. The purified product is dried under vacuum,resulting in the formation of a solid,bis(4-aminobenzimidazole)perylene.

Subsequently, 1.50 grams (2.5 millimoles) ofbis(4-aminobenzimidazole)perylene is stirred in an aqueous solutioncontaining 10 milliliters of concentrated hydrochloric acid and 10milliliters of water at about 60° C. for 1 hour and then overnight atroom temperature. The resulting dispersion is then cooled to 0° to 5° C.by an ice water bath, and a cold aqueous solution of sodium nitrite (0.8gram in 2 milliliters of water) is added dropwise over 15 minutes. Tothe dispersion thus obtained is then added about 700 milliliters of coldwater, and the mixture is filtered, followed by the addition of 30milliliters of HBF₄ to the filtrate, resulting in the formation of aprecipitate which is the tetrazonium salt ofbis(4-aminobenzimidazole)perylene. The product is isolated by filtrationand purified by washing with a small amount of cold methanol and etherto yield the tetrazonium product. The tetrazonium salt is then dissolvedin about 100 milliliters of cold dimethyl formamide inside a 1 liter 3neck flask surrounded by an ice water bath. A cold dimethyl formamidesolution containing 1.31 grams of 2-hydroxy-3-naphthanilide, availablefrom Aldrich Chemical Company, in 100 milliliters of dimethyl formamideis added to the salt solution. Subsequently, a cold aqueous solution ofsodium acetate (2.67 grams of NaOAc in 40 milliliters of water) is addeddropwise to the solution, resulting in formation of a precipitate. Theprecipitate is stirred at room temperature overnight, followed byisolation of the product by filtration. The product is then purified bywashing twice with 150 milliliter aliquots of water at 80° C., followedby washing three times with 150 milliliter aliquots of dimethylformamide at 80° C., subsequently washing with 150 milliliters ofacetone, and then washing with 150 milliliters of diethyl ether,resulting in a mixture of the photogenerating compounds of the formulaeindicated above (cis and trans isomers).

EXAMPLE VI

An imaging member is prepared with the photogenerating pigment preparedas described in Example V as follows. To a 1 ounce amber bottle there isadded 52.8 milligrams of polyvinyl formal (obtained from ScientificPolymer Products, Inc., formal content 82 percent, acetate content 12percent, hydroxy content 6 percent) and 10 milliliters oftetrahydrofuran. The bottle is placed on a Wrist Action Shaker and thepolymer is dissolved in the tetrahydrofuran. Subsequently, 211.2milligrams of the photogenerating material prepared in Example V andabout 85 grams of steel shots (1/8 inch diameter stainless steel shot)are added to the bottle and the bottle is placed on a Red Devil PaintConditioner (Model 5100X) and shaken for about 30 minutes. The resultingdispersion is coated onto a 7.5 inch by 10 inch fire-cleanedbrush-grained aluminum substrate obtained from Ron Ink Company using aGardner Mechanical Drive with a 6 inch wide Bird Film Applicator (0.5mil wet gap) inside a humidity-controlled glove-box. The relativehumidity is controlled to less than 25 percent. The resulting chargegenerator layer is air-dried for about 30 minutes and then vacuum driedfor about 1 hour at 100° C. to result in a charge generator layer with athickness of about 0.4 micron.

The above charge generator layer is overcoated with a charge transportlayer prepared as follows. A solution containing 4.2 grams of Makrolon®,a polycarbonate resin obtained from Larbensabricken Bayer A. G., 2.8grams of N,N'-bis (3"-methylphenyl)-1,1'-biphenyl-4,4'-diamine preparedas disclosed in U.S. Pat. No. 4,265,990, the disclosure of which istotally incorporated herein by reference, is prepared by dissolving theabove materials in 31 milliliters of methylene chloride inside a 2 ounceamber bottle. The transport layer is obtained by coating the solutiononto the charge generator layer using a 3.5 inch wide, 5 mil wet gapBird Film Applicator, resulting in a transport layer about 25 micronsthick. The resulting photoconductive device is air dried for about 1hour and vacuum dried at 100° C. for about 16 hours before electricaltesting.

The imaging member thus prepared is evaluated as described in ExamplesII and IV. It is believed that the imaging member will exhibitphotosensitivity in the wavelength range of 400 to 720 nanometers withproperties substantially similar to the member of Example II.

Other embodiments and modifications of the present invention may occurto those skilled in the art subsequent to a review of the informationpresented herein; these embodiments and modifications, as well asequivalents thereof, are also included within the scope of thisinvention.

What is claimed is:
 1. An imaging member which comprises a conductivesubstrate and a photogenerator layer containing a photogeneratingcompound of the formula: ##STR27## wherein Cp represents a couplergroup.
 2. An imaging member according to claim 1 also containing acharge transport layer.
 3. An imaging member according to claim 2wherein the photogenerator layer is situated between the conductivesubstrate and the charge transport layer.
 4. An imaging member accordingto claim 2 wherein the charge transport layer is situated between theconductive substrate and the photogenerator layer.
 5. An imaging memberaccording to claim 1 wherein the conductive substrate is a metal.
 6. Animaging member according to claim 1 wherein the conductive substrate isaluminum.
 7. An imaging member according to claim 1 wherein thephotogenerator layer has a thickness of from about 0.05 to about 10microns.
 8. An imaging member according to claim 1 wherein thephotogenerating compound is dispersed in a resinous binder in an amountof from about 5 percent by weight to about 95 percent by weight.
 9. Animaging member according to claim 8 wherein the resinous binder isselected from the group consisting of polyesters, polyvinyl butyrals,polycarbonates, and polyvinyl formals.
 10. An imaging member accordingto claim 2 wherein the charge transport layer comprises an aryl aminecompound.
 11. An imaging member according to claim 10 wherein the arylamine is of the formula: ##STR28## wherein X is selected from the groupconsisting of alkyl and halogen and wherein the aryl amine is dispersedin a highly insulating and transparent organic resinous binder.
 12. Animaging member according to claim 11 wherein X is selected from thegroup consisting of ortho (CH₃), meta (CH₃), para (CH₃), ortho (Cl),meta (Cl), and para (Cl).
 13. An imaging member according to claim 11wherein the resinous binder is selected from the group consisting ofpolycarbonates and polystyrenes.
 14. An imaging member according toclaim 1, wherein the coupler group is selected from the group consistingof ##STR29## wherein X₁ is selected from the group consisting of --OH,--NR₁ R₂, and --NHSO₂ --R₃ (wherein R₁ and R₂ are selected from thegroup consisting of hydrogen, substituted alkyl groups, andnon-substituted alkyl groups, and R₃ is selected from the groupconsisting of substituted alkyl groups, non-substituted alkyl groups,substituted aryl groups, and non-substituted aryl groups), Y₁ isselected from the group consisting of hydrogen, halogens, substitutedalkyl groups, non-substituted alkyl groups, substituted alkoxy groups,non-substituted alkoxy groups, carboxyl groups, sulfo groups,substituted sulfamoyl groups, non-substituted sulfamoyl groups, and##STR30## wherein R₄ is selected from the group consisting of hydrogen,alkyl groups, substituted alkyl groups, phenyl groups, and a substitutedphenyl groups, and Y₂ is selected from the group consisting of cyclichydrocarbons, substituted cyclic hydrocarbons, heterocycles, andsubstituted heterocycles, and ##STR31## wherein R₅ is selected from thegroup consisting of cyclic hydrocarbons, substituted cyclichydrocarbons, heterocycles, and substituted heterocycles and R₆ isselected from the group consisting of hydrogen, alkyl groups,substituted alkyl groups, phenyl groups, and substituted phenyl groups,and wherein R₅ and R₆ may form a ring, Z is selected from the groupconsisting of cyclic hydrocarbons, substituted cyclic hydrocarbons,heterocycles, and substituted heterocycles, n is an integer of 1 or 2, mis an integer of 1 or 2, R₇ is selected from the group consisting ofsubstituted hydrocarbonyl groups and non-substituted hydrocarbonylgroups, R₈ is selected from the group consisting of alkyl groups,carbamoyl groups, carboxyl groups, and carboxyl esters, Ar₁ is selectedfrom the group consisting of cyclic hydrocarbons and substituted cyclichydrocarbons, R₉ is selected from the group consisting of hydrogen,substituted hydrocarbonyl groups, and non-substituted hydrocarbonylgroups, and Ar₂ is selected from the group consisting of cyclichydrocarbons and substituted cyclic hydrocarbons.
 15. An imaging memberaccording to claim 1, wherein the coupler group is selected from thegroup consisting of ##STR32## wherein R is selected from the groupconsisting of substituted and non-substituted aliphatic hydrocarbon withfrom 1 to about 20 carbon atoms and Ar is selected from the groupconsisting of substituted and non-substituted aromatic hydrocarbon groupwith from 6 to about 24 carbon atoms and substituted and non-substitutedheterocyclic moieties; ##STR33## wherein R is selected from the groupconsisting of substituted and non-substituted aliphatic hydrocarbon withfrom 1 to about 20 carbon atoms and Ar is selected from the groupconsisting of substituted and non-substituted aromatic hydrocarbon groupwith from 6 to about 24 carbon atoms and substituted and non-substitutedheterocyclic moieties; ##STR34## wherein R is selected from the groupconsisting of substituted and non-substituted aliphatic hydrocarbon withfrom 1 to about 20 carbon atoms and Ar is selected from the groupconsisting of substituted and non-substituted aromatic hydrocarbon groupwith from 6 to about 24 carbon atoms and substituted and non-substitutedheterocyclic moieties; ##STR35## wherein R is selected from the groupconsisting of substituted and non-substituted aliphatic hydrocarbon withfrom 1 to about 20 carbon atoms and Ar is selected from the groupconsisting of substituted and non-substituted aromatic hydrocarbon groupwith from 6 to about 24 carbon atoms and substituted and non-substitutedheterocyclic moieties; ##STR36## wherein X is selected from the groupconsisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, l, NO₂, CF₃, OCH₃, OC₂H₅, CN, NH₂, and OH and n is 0, 1, 2, or 3; ##STR37## wherein X and Yare independently selected from the group consisting of H, CH₃, C₂ H₅,C₃ H₇, Cl, F, Br, l, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, and OH, m is 0, 1,2, 3, or 4, and n is 0, 1, 2, or 3; ##STR38## wherein X is selected fromthe group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, l, NO₂, CF₃,OCH₃, OC₂ H₅, CN, NH₂, and OH and n is 0, 1, 2, or 3; and ##STR39##wherein X is selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇,Cl, F, Br, l, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, and OH and n is 0, 1, 2,or
 3. 16. A method of imaging which comprises generating anelectrostatic latent image on an imaging member of claim 1, developingthe latent image, and transferring the developed electrostatic image toa suitable substrate.